Teac X2000R tension arm oscilation

[TheReeler]

As I said in other topic (http://www.tapeheads.net/showthread.php?t=1190), the tension arms of my Teac X2000R sometimes oscilate up and down and if I put my finger against it to stop that fluctuation, usually makes that the tension arm stays quite but finally it ends making the armonic oscilation again.

Here is a video shot now that shows what's happen:

http://www.youtube.com/watch?v=14Lc7sqPKcw

With this tape, the fluctuation didn't appear at the begin of the tape but appeared at the end, in both play directions.

Can be done a diagnostic after watching the video? *hope*

PD: The video has been uploaded to YouTube using good quality, so if you don't watch it well, try to click in the "watch it in high quality" link that is down the video rectangle.

[Scorpion8]

I watched the video. I didn't really see a whole lot of oscillation. But... do you have the SM? It's possible that whatever spring tension/return mechanism is used on those is either getting worn, or needs some lube to operate smoothly. I have no experience with that model so someone else (Matt?) may chime in with more direct experience.

[TheReeler]

Yes, I have the SM but don't know exactly which thing can cause this issue. The deck runs OK except this "little failure" and maybe Sam or others know what's happen only viewing the video.

Both bearings run smoothly and sometimes is the left tension arm which oscillates, sometimes is the right or even both.

[niklasthedolphin]

As I said in other topic (http://www.tapeheads.net/showthread.php?t=1190), the tension arms of my Teac X2000R sometimes oscilate up and down and if I put my finger against it to stop that fluctuation, usually makes that the tension arm stays quite but finally it ends making the armonic oscilation again.

Here is a video shot now that shows what's happen:

http://www.youtube.com/watch?v=14Lc7sqPKcw

With this tape, the fluctuation didn't appear at the begin of the tape but appeared at the end, in both play directions.

Can be done a diagnostic after watching the video? *hope*

PD: The video has been uploaded to YouTube using good quality, so if you don't watch it well, try to click in the "watch it in high quality" link that is down the video rectangle.

May I ask if the problem is the same if you play tape with equal size reels in both sides?

"dolph"

[Scorpion8]

Examine the tape. If the tape is coming off the reel pack sticky, that would cause the arms to fluctuate with changing tension and it would then depend which side the reel supply pack was on, left or right.

[Web Police]

I second the different size reels theory. Does it do the same thing with two equal size reels? Every RTR deck I have ever had recommended using two reels of the same size. Also from the video is it hard to tell but the small reel looks like it is out of round, or possbbly the shaft on the left reel is bent?

[TheReeler]

May I ask if the problem is the same if you play tape with equal size reels in both sides?

"dolph"
Yes, occurs the same, doesn't matter if both reels are 7" or 10.5" or different.

About the tape, occurs even with the best ones: 1.0 mil as Maxell XLI or Maxell UD and 1.5 mil as Quantegy GP9 or Basf 911. No sticky tapes here.

[TheReeler]

Also from the video is it hard to tell but the small reel looks like it is out of round, or possbbly the shaft on the left reel is bent?
None of the shafts are bent, they're perfectly straight.

[Web Police]

Ok, just checking out the obvious first. Let's see what ideas Des can come up with. :-?

[Des-Lab]

I watched the vid too. First thought that came to my mind too was the possibility of bad tape. As Reeler insists that it does it with all tapes and that they are in good condition, that rules that out.

Reel size differential shouldn't be a factor because the deck is logic/tension controlled. And the tension should be compensated for. This is why the X-2000R doesn't even HAVE a Large/Small reel size setting.

Someone else mentioned the possibility of the idler rollers being bent. Have you tried rotating them from left side to right and vice versa and see what happens?

The caps can be easily unscrewed by hand and the rollers swapped. Try that and see what happens.

Another possibility also as noted is that either the spindle on the reel table or possibly the reel itself might be warped or not true to center. But again the OP has affirmed this to not be true. The easiest way to crosscheck that is to see the wind at high speed. If there is any warpage or offset, then at fast wind, there will be some vibration and shaking and the reel noticably wobbling-depending on how severe.

The only other thing I can think of is that the tension itself might be slightly off. In which case you will need to open the deck up and adjust the two small tension pots located inside.

[TheReeler]

I watched the vid too. First thought that came to my mind too was the possibility of bad tape. As Reeler insists that it does it with all tapes and that they are in good condition, that rules that out.

Have tested now again with both reels of same size, and stil happening.



Someone else mentioned the possibility of the idler rollers being bent. Have you tried rotating them from left side to right and vice versa and see what happens?

The caps can be easily unscrewed by hand and the rollers swapped. Try that and see what happens.

Didn't know that were easy to swap. I've just done it right now and the effect still happening, but have noticed that in the external part of the roller, between it and the cap, is a small washer. It only had in one of the rollers, so there's one missing, but I've put it in the left roller, which is the one that is oscillating now, and the effect stills happening.


The easiest way to crosscheck that is to see the wind at high speed. If there is any warpage or offset, then at fast wind, there will be some vibration and shaking and the reel noticably wobbling-depending on how severe.

Tested now again and both reel tables are perfectly centered and both spindles are perfect. There's no oscillation of any kind.


The only other thing I can think of is that the tension itself might be slightly off. In which case you will need to open the deck up and adjust the two small tension pots located inside.
I had though it in first place, but I'm not sure if this is the reason or not, and as I don't have a tentel... it's really difficult to set propertly the tension without it in a machine that is logic/tension controlled. When I set up the Grundig TS-1000, I adjusted the tension but I think I was lucky that time.

[TheReeler]

Didn't know that were easy to swap. I've just done it right now and the effect still happening, but have noticed that in the external part of the roller, between it and the cap, is a small washer. It only had in one of the rollers, so there's one missing, but I've put it in the left roller, which is the one that is oscillating now, and the effect stills happening.

And that's was the reason!!!! *hypnot*

Each tension arm has two washers, one at each side of the bearing and the one that was missing, was the most external. Well, I've looking for a replace and found at home other similar. I tried it, but it did lot of noise because it was made of metal, not of teflon, so I found one made of teflon opening an old microprocessor fan. The washer is not identical to the originals, but is made of teflon, so I put it in the most internal part of the left arm, and the original in the external part.

Well, I'm listening a tape and after 1 hour, it didn't oscillate!!!!!!!

Thanks to everyone, I'm sure I've solved the problem thinking in your suggeriments *Hi5*

PD: Still spinning the Quantegy GP9 recorded with some Pink Floyd's albums

[TheReeler]

ARRRRRRRRRRGGGGGG!!!!!!!! *flame* *flame* *flame* *flame* *flame* *flame*

Now I'm listening a 7" Maxell tape and it stills happening *?conf?

If I get the left tension arm with two fingers, and push it or pull it, it becames to oscillate very fast, but there's a position where it gets stopped and doesn't oscillate.

Any clue?...

[TheReeler]

Well, now I think the problem is fixed. I shot some hidef videos so that they can be watched with some quality so the "Watch this video in high quality" link will appear under the video window.

I opened the deck trying to figure out which was the problem. The auto-tension system is basically the same as the one found in the Grundig TS-1000. Each tension arm has a small plate attached in the inside and passes near a photodetector so that when the tension arm is in the lower position, the motor power goes up, and when the arm goes to a higher position, the tension applied to the motor goes down.

http://es.youtube.com/watch?v=FeZChKf33Ms


I tried to adjust the position of the photodetectors and even the trimmers that adjust the tension, but no luck, the problem still happening.

The tension arm axis is a screw that has springs. I realized that when I manipulated the screw, the height position of the tension arm varied. I adjusted this screw with the machine in play mode with a tape threaded so that I can watch the results in real time. I minimal adjustement was needed to watch the tension arm stops its oscillation.

In appearance, this was a rare failure, because most times whis happen is caused by old motors and/or poor lubricated rollers and arms, but in this case, both rollers are in perfect shape and the motors too.

Here is another video with the final result after the adjustement:

http://es.youtube.com/watch?v=qRvBr_iJAwk

And finally, I shot this video showing some inside views of the deck and how the capstan belt changes its position depending on which play direction is selected. This happen because the capstan wheels have two parts, one with a diameter bigger than the other, so that when the forward direction is selected, the belt accomodates the position where the right capstan wheel spins a little faster than the left one, and the opposite, when the reverse direction is selected, the left capstan wheel spins a little faster than the right capstan wheel.

http://es.youtube.com/watch?v=ATY-S3L-8rg

Hope you enjoy :)